Note: Descriptions are shown in the official language in which they were submitted.
~L3~2~3~
Edible Films of Collagell, with a Content of Gluten,
in Particular wheat Gluten, a Process for the Production of
These, and the Use of Such Films for Encasing Foodstuffs
The present invention relates to edible films (tubular and sheet films)
based on colla~en, in which part of the collagen has been replaced by ~luten,
in particular by wheat ~luten, a process for the production of said films, and
the use of such films for encasin~ foodstuffs.
Gluten is the adhesive protein of bresd stuff~ - see Roempps Chemie
Lexikon (Albrecht ~eumuller Edltor) 8th Edltion (1931) page 1511, Keyword
"Gluten". Wheat gluten i~ a typical glute~, and ls known in the Federal
German Republic under the trade-mark Weizen-Vital-Kleber (WVK~. Wheat
gluten represents the protein fraction of wheat kernels, which is composed of
various protèin components. It is obtained as a by-product from the extraction
of wheat starch from ~round wheat. Wheat meal is stirred to a paste with
water and the starch fraction eluted as thin starch paste during constant
Xneadin~, The wheat starch contains approximately 85% of the total protein of
the wheat meal, w~ich remains in the form of the easily perishable moist
~luten, an unstable cohesive-elastic mass with a water content of
approximately 60-70~ and is ~enerally dried, under the best possible,
carefully controlled conditions, to form a storable product with an average
moisture content oP 6-7~. The protein content of the ~luten produced in
Germany is about 80% (N . 6.25) to 85~, relative to the dry weight of the
substance. The remainder consists of fats, carbohydrates, and minerals.
Tubular films, used in particular as sausa~e cssin~s, as well as flat
films of colla~en have already been known for some time. These are produced
in a known manner by breakin~ down animal skins. The startin~ material in
this case is a colla~en slurry with a collagen content of approximately 2 to
15h dry colla~en that is then formed in a known manner into a film. In
thinner colla~en slurries of, for example, 2 to 5~, the colla~en film is
coa~ulated in a precipitation bath (the so-called wet method), whereas
colla~ens slurries with higher collagen contents of, for example, lO to 12%,
are extruded from the slurry to form a self-supportin~ tube, without the use
of a coa~ulatin~ bath.
Sausage casin~s of colla~en have the advanta~e of bein~ edible, and for
this reason have come to be used very extensively.
A PAT 10901-1
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Hany attempts have already been made to replace the collagen in these
sausage casin~s with other materials, either completsly or in part. Exsmples
o~ this are seen in sausa~e casin~s of cellulose hydrata, although these
entail the disadvantage of bein~ inedible, with the result that the sausa~e
manufacturer has to remove them from the ina1v~dual sau3Ages before they are
supplied to the consumer. Attempts have also been mad~ to replace tha edible
collagens in sausa~e casings with other edible mater~als such as amylose,
al~inic acid or calcium albinate, respectively or with laetic protein.
Although such casin~s are edible in principle, such caslngs are of no practical
importanc~ because these products used to replace the colla~en do not have the
favourable processin~ and utility characteristics of pure colLa~en. It has
been more the case that such replacemen~ products for the collagen, or
products in which the colla~en has been replaced e~ther totally or ln part, do
not possess the physical test values and ~he ut~lity characterlstics of pure
collagen film.
For this reason, it is the ob~ect of the present lnvention to provlde a
film in which a considerable p~oportion of the colla~en can be replacsd by a
readily available, economical additive without pre~udice to the favourable
characteristics of the pure collagen f~lm.
The word "film~ hereinafter understood to mean both flat and tubular
films.
Accordin~ to the present invention, th;s ob~ective has been attained by a
film which, relative to 100 p/wt (parts by wei~ht) of dry colla~en, contains 1
to 100 p/wt, preferably 2 to 50 p/wt, and in particular 5 to 20 p/wt, of,
~luten.
~he use o~ ~luten for the production of foodstuffs psckaging ls already
known; however, this usually involves either packa~es, such as cook-in ba~s,
that are of pure gluten, as described in U.S.P 3,062,664~ or a film which
contains up to 50~ of other ve~etable protein, for example, zeln or soya
protein as well as other components in addltion to gluten, as is described in
U.S.P. 3,653,925. Such films are poured from an ammoniac, water-alcohol
dispersion, using a softenin~ a~ent.
Host surprisin~ly, the addition of ~lutens to the colla~en has no ne~ative
effects on the physical properties and ut~lity characterl3tics of the
colla~en, in contrast to the addition of other proteins, such as soya proteln,
PAT 10901-1
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zein, keratin, casein, or blood plaqma; in~eed, despite a considerable
proporti~n of sluten, the sausa~e casin~s and films aceordin~ to the present
invention display practically the same properties AS films of pure colla~en.
In particular, tear resistance remains unaffected. This could not have been
~oreseen becuase the mechanical strength of the collagen is known to be
reduced by additives such as cellulose or ~he colourin~ pi~ments that are
used, which are alien to the colla~en; the additlon of other pro~eins also
de8rades the properties of the collagen. Also surprisin~ is the fact that the
thermal welding properties of the product are improved by the addlt~on o
10 gluten.
Such films with a gluten content of up to 50~-wt stlll possess perfectly
acceptable characteristics, the use of gluten, which i8 only half the prlce of
collagen and is readilr obtainable, rapresents a considerable sav~ng in
costs. A further advanta~e of the film accordins to the present invention has
been shown in field tests:
To a very great extent, the addition of sluten levels out the fluctuations
in the properties of colla~en which result from the variou~ ori~ins and
histories of the colla~en sources.
The production of the fil~s accordin~ to the present invention is
acco~plished by a process that also constitutes part of the present invention,
by mixing 10 t 100 p/wt of gluten, relative to 100 p/wt of dry colla~en, with
the collagen, whereupon the mixture so obtained is formed into tubular or flat
fllm stock in the known manner.
It has been proven to be particularly advantageous to mix in the ~luten in
the form of an acidic dispersion. In light of the state of the art~ this was
not appropriate since, up to now, ~luten had always been processe~ into films
from alkaline dispersions.
The addition of the gluten in sn acidic dispersion mean~ that the p~ value
of the colla~en, which is between 2.5 and 3.0, remains unchanged for all
practlcal purposes, which is advanta~eous.
Host sdvanta~eously, the ~luten is us2d in d~lute~, ~eakly acidic
dispersion. Such diluted dispersions with ~luten contents of up to 20~wt in
ln acetic acld are thin-bodied and homogeneous; at hi~her concentrations of up
to 27l-wt they become medium ~iscous and remain homogeneous. According to the
present invention, it is preferred that the glu~en be produced in a 10
PAT 10901-1
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dispersion in ln acetic acid by dispersion, using a suitable apparatus- e.~.,
Vltraturrax~(Jahnke & Kunkel, Staufen/Breisgau~and then processed in the
desired mix ratio into a ready-for-use collagen slurry.
The colla~en slurry that is used can contain more or less colla~en,
calculated as dry collagen, depending on the process that is used. As a rule,
a diluted colla~en slurry has a collagen content of 2 to 6~, and is processed
according to the so-called wet process. A more highly concentrated colla~en
slurry contains approximately 6 to 12% dry coLlagen. Vsing such a slurry, one
ususlly employs the dry process.
The film according to the present invention may contain additional
components, such as softening agents, fillers and/or tanning agents, in
addition to collagen and gluten. Propylene glycol and sorbitol, as well as
mixtures of these compounds, make suitable softening agents, in addition to
glycerine. The quantity of softening agent amounts to O to 50, preferably
5-40~-wt, relative to the dry collagen. The filler additive is in the range
of O - 40, preferably 5-30~-wt. Cellulose powder is particularly suitable as
a filler. The film contains O to 5, preferably 0.01-4, and in particular 0.1
to 3~-wt tanning agent, once again relative to the dry collagen. Aldehydes
such as glutaraldehyde or aldehydes that contain liquids, such as wood-smoXe
distillate, are suitable as the tanning agents.
Whereas components such as fillers and a part of the so~tening agent, and
optionally aldehydes used as tanning agents can be mixed into the collagen
starting slurry, continued tanning is effected advantageously by treating the
finished film with an aqueous tanning agent solutiqn, for example, aluminum
sulfate solution.
As an example, a collagen mixture suitable for the production of tubular
film to be used for sausage casings contains 6 to 10~-wt collagen, relative to
the dry collagen, 5 to 30~-wt cellulose powder (as a filler), 10 to 401~wt
softening agent, and 0.01 to 1.0~ aldehyde, relative in each instance to the
dry collagen.
Once the gluten has been mixed homogeneously with the collagen that
contains water, the slurry that has been so obtained is formed in the Xnown
manner into flat or tubular films. The production of the tubular film is
effected either by precipitating a diluted collagen solutlon in a coagulation
bath or by extruding a high-concentration slurry through an extruder, with
* Trade Mark
PAT 10901-1
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which a longitudinal and transve~sa orientation of the colla~en fibres ln the
s~truded tube is achieved; thls is followed by known, additional processin~ or
production sta~es such as drying, tanning, thermal hardenin~, and shrinkin~.
In the production of edible sausage casings, the mixtures of collagen and
~luten so produced do not dlffer from pure collsgen casings without added
Bluten- In all the production sta~es ~extrusion, d~ying in a drying tunnel,
hardsning, conditioning, and shr~nking) the result~ng sausa~e casln~s behave
in the same manner as casings without the addition of gluten.
Aqueous suspensions with O.S to 4% collagen are prepared ln order to
produce edible collapen films. In addition to collagen, this slurry contains
0 to 30% cellulose powder, 10 ~o 40% softening agent, 0 to 1% sldehyde,
relative to the dry collagen. In addition, 1 to S0~, preferably 10 to 30~,
~luten is prepared as a 10% dispersion in ln acetic acid in the collagen
slurry.
In the production of edible collagen films, there is no difference in
behaviour between films with added ~luten, and those without it.
The invention wlll be described in ~reater detail below by way of the
following example.
Example 1:
a) S00 X~ of s~fted collagen with a dry-material content of 13.60h and a pH
value of 3.0b was mixed with the following addit~ves:
L .
Cellulose powder 5.0 kg
Water 281.75 litres
Glycerine20.25 litres
Hydrochloric acid 30% 0.9 litres
This resulted in a casin~s slurry with a dry-material co~tent of 11.52~.
b) In order to produce a ~luten dispersion, 100 parts lN acetic acid were set
aside and 11 parts of commercial ~luten were added to this and homogenized
with the Ultraturrax.
c) 100 parts of prepared casings slurry with a colla~en con~ent of ~.4 parts
PAT 10901-1
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~1 311 22~
~r~ placed in a Z-knead~r and thorou~hly mixed with 8.4 parts of gluten
disi ~rsion as in b~, during slow addition.
d) The slurry so obtained was extruded in air in the conventional manner,
through a tubu.Lar die of 21 mm diameter and 0.45 ~m slot width, with a
rotating core as in published DE-PS 650 887 (Naturin-Werke Becker~ 9 filed
August 8, 1930; the resultlng tube was lnflated from
the inside with air and passed through a drying tunnel. After the first
drying the tube was neutralized with a bicarbonate solution that contained
glycerinel the tube was then washed with water, dried onc~ again, and
rolled up flat. Finally, the tube was heated slowly to thermally harden
it tor 4 hours at 90.
e) The casings were then filled in the usual way with wiener and bratwurst
mixtures prepared according to various recipes, and cooked. When the
sausages were boiled or fried, these casings behaved no differently from
sausage casings produced in the same manner but without the added gluten.
f) The physical properties of the casings so obtained are set out in Table l.
Example l was repeated, using other nozzle dimensions and/or doubling up
on the proportion of gluten as is shown in the following table:
ExampleGluten Diameter / Gap Diameter ~ Gap
% 21 mm 0.45 mm 23 mm 0.6 mm
X X
2 20 X X
Comp. 1 0 X X
3 10 X X
4 20 X X -
Comp. 2 0 X X
In order to mix in 20~ gluten, 100 parts of collagen was mixed with 16.8
parts of the gluten dispersion as in la).
In the practical test in the application technology section, the casings
PAT lO90l-l
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displayed characte~-istics that were as good as conventional collagen casin~s
without gluten. Their physical characteristics were close to those of the
compa~ative example and are shown in Table 1.
Exam~le 5:
b) 100 parts of p~epared colla~en slurry with a collagen content of 2~ was
placed in a container with a mixing turbine and thorou~hly mixed with 4
parts of commercial wheat-~luten dispersion (WVK) as in Example la).
c) The slurry so obtained with 20% wheat ~luten, relative to the collagen,
was extruded through a slit-type nozzle having a ~ap 0.4 mm lon~ and 0.5
mm wide onto an endless plastic strip and then passed at 10 m/min at an
air temperature of 60C through a dryin~ tunnel. The f.ilm W8S then
removed from the strip and rolled up lnto rolls.
d) In the application technology sec~ion, the films were tested for encasing
~Icooked ham in a net", using an apparatus as in EP-A-0175173
(Naturin-Werke Becker) published March 26, 1986, and were found to perform
as well as conventional collagen films without any added gluten.
e) The physical data for the films so obtained are set out in the following
Table 2:
Phvsical Data--Colla~en Foils Containin~ 20% Gluten
Example Gluten Tear Value -- Dry Films
Content Lonsitudinal Transverse
~ N N
6.7 9 4
Comp. 3 0 6.8 9.7
PAT 10901-1
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13~23~
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